Microsurgical Anatomy Of Anterior Circulation Of Willis Circle And Its Perforating Branches

Objective To study the microanatomy of anterior circulation of Willis circle and its perforating branches to provide anatomical data for neurosurgeons.Methods The microsurgical anatomy of the anterior portion of the arterial circle of Willis in 5 cases(10 sides) of adult cadaver heads fixed in formalin was observed under microscope.The configuration and pathway of vessels were obtained.Results Many variations were found in the diameter,length and origin of the ACA,ACoA and their perforating branches.Hypoplasia was common in the right A1 segment and the diameter of the left A1 was larger than that of the right one.Most perforating arteries of arose from superior, medial-superior A1 segments and coursed poster-superiorly,A1 segment sent branches then supply the anterior perforated substance,basal nuclei, optic chiasm,frontal lobe and hypothalamus.All of Heubner recurrent arteries arise from the anterior cerebral artery,and usually near anterior communicating artery.Recurrent artery of Heubner courses anterior,superior or posterior to A1 segment of anterior cerebral artery. The recurrent artery of Heubner was the thickest branch of the ACA-A1 segment and the location of its origin was in the range of 3cm proximally to 3cm distally.Few perforating arteries were found within 3-5mm proximally and middle 1/3 of the ACA-A1 segment.The shape of ACoA varied. Its perforating branches supplied hypothalamus,OC and genu of corpus callosum,et al. Conclusion Many anatomical variations were found in A1 segment of ACA,Dominant A1 segment of anterior cerebral artery is much more frequently found in patients with ACoA aneurysms.We found many anatomical variations were in Heubner recurrent arteries.So,To understand the microsurgical anatomy of the Willis circle and protections against its penetrating branches perfectly are the key to gain a good curative effect during the concerned operation.